The Kremlin says all five aboard a Russian military helicopter downed in Syria have been killed.

"From what we know from information provided by the Defense Ministry, all those who were on the helicopter died," spokesman Dmitry Peskov said on August 1.

Peskov said the Russians "died heroically because they tried to move the aircraft away so to minimize losses on the ground."

Earlier, the Defense Ministry said an Mi-8 transport helicopter had been shot down over the province of Idlib but that the fate of the five people onboard -- three crew members and two officers -- was unknown.

The ministry said the aircraft was returning to the Russian air base on the coast after delivering humanitarian aid to the northern city of Aleppo.